Week 3: Gene Expression And Basic Molecular Techniques Flashcards
What are the seven key points for control from DNA to protein?
- Transcription control
- RNA processing
- Transport and localisation
- Translational control
- RNA degradation
- Protein degradation
- Protein activation
These points outline the stages at which gene expression can be regulated in eukaryotic cells.
Why is gene expression control necessary in multicellular organisms?
Differential gene expression is needed for specific cell types or at specific times
Even though DNA content is identical in all cells, different cell types have unique functions requiring regulated gene expression.
What are ‘housekeeping’ genes?
Ubiquitously expressed genes necessary for basic cellular functions
Examples include genes involved in protein synthesis (e.g., rRNA genes) and energy production (e.g., ATPase).
What is temporal regulation in gene expression?
Regulation based on the developmental stage, differentiation stage, or cell cycle stage
For example, globin gene expression varies with developmental stages.
What is transcription control?
Regulation of whether transcription occurs, often through epigenetic mechanisms
This includes the binding of transcription factors to promoters.
What role do transcription factors play in gene expression?
They bind to promoters and guide RNA polymerase II for transcription initiation
Transcription factors can be ubiquitous or tissue-specific.
What is alternative splicing?
A process that allows different combinations of exons to produce tissue-specific protein isoforms
This contributes to the diversity of proteins produced from a single gene.
What is the effect of histone acetylation on transcription?
Activates transcription by making chromatin less condensed
In contrast, histone methylation can silence transcription.
What are the two main mechanisms of RNA degradation in eukaryotic cells?
- 5’ cap removal
- 3’ degradation
Both mechanisms begin with the shortening of the poly-A tail.
What is the purpose of cloning DNA?
- Study the DNA
- Express the protein it makes
- Mutate the DNA
- Understand the gene better
- Make enough copies for laboratory work
- Change organism characteristics
Cloning techniques include cell-based and cell-free methods.
What are the four key stages of cell-based DNA cloning?
- Cutting a target DNA
- Inserting the target DNA into a plasmid
- Introducing the plasmid to bacteria or yeast
- Identifying the bacteria or yeast with the plasmid insert
This process allows for the propagation of specific DNA sequences.
What is PCR?
A method for selective amplification of a specific target DNA sequence
PCR is performed in vitro and can amplify DNA from a complex mixture.
What is nucleic acid hybridisation?
A method where single-stranded DNA or RNA molecules combine to form double-stranded molecules
It often involves a labelled probe to identify related nucleic acids.
What are some applications of DNA hybridisation?
- PCR - annealing of primers
- Dot blot hybridisation
- Southern blot hybridisation
- Northern blot hybridisation
- Colony blot hybridisation
- Chromosome in situ hybridisation
These techniques are used to study gene expression and DNA sequences.
Fill in the blank: Transcription control involves the binding of _______ to promoters.
transcription factors
These factors are crucial for the initiation of transcription by RNA polymerase II.
